Doit.im - Doit.
Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
TaskUnifier - TaskUnifier - Task Management Application
TickTick - TickTickis a cross-platform to-do list app & task manager helps you to get all things done and make life well organized.
The Hit List - Your life is complicated, but managing it doesnt need to be.
Makagiga - Makagiga is an all-in application that is known for doing a variety of tasks such as one to-do manager, note-taking, to-do listing, and RSS reading.